#include <bits/stdc++.h>
using namespace std;
#define yes cout<<"YES"<<endl
#define no cout<<"NO"<<endl
using ll = long long;
void solve()
{
    priority_queue<int,vector<int>,greater<int>> q;
    for(ll i=1;i<=4;i++)
    {
        q.push(i);
        
    }
    while(!q.empty())
    {
        cout<<q.top()<<endl;
        q.pop();
    }
}
int main()
{
    int t = 1;
    //cin >> t;
    while(t--)
    {
        solve();
    }
   return 0;
}
